Moisture absorbing means in radial flow turbines



Oct. 3, 1961 3,002,725

MOISTURE ABSORBING MEANS IN RADIAL FLOW TURBINES K. W. LJUNGBERG ET AL Filed Feb. 3, 1958 FIG. 7.

United States Patent 3,002,725 MOISTURE ABSORBING MEANS IN RADIAL FLOW TURBINES Klas Wilhelm Ljungberg, Sodermalmsvagen 16, and Anders A Skog, Gronavagen 25A, both of Finspang, Sweden Filed Feb. 3, 1958, Ser. No. 712,890 Claims priority, application Sweden Feb. 7, 1957 1 Claim. (Cl. 253-165) This invention relates to means for separating moisture from steam after having expanded in a radial flow turbine with an exhaust diifuser. If the moisture were allowed to enter into the low pressure turbine the material of the turbine would be subjected to corrosion and erosion. The water particles deposited on the rotating members would be thrown by the action of the centrifugal force onto the guide blades, turbine-walls and other members of the turbine which would be worn and destroyed by such a bombardment of water particles. In addition, the moisture may reduce the efliciency of the turbine due to the fact that the water particles will be accelerated by the steam, said steam thereby depriving the steam of part of its energy.

The object of the invention is to effectively remove said moisture before it reaches the low pressure turbine.

To this end there are provided between the radial extending annular side walls of the diifuser a set of circumferentially spaced partitions. Said partitions are preferably located in planes slightly inclined with relation to the axial planes that may extend through the inner ends of the partitions. The surfaces of the partitions onto which the moisture particles will be thrown from the outermost blading of the radial flow turbine are provided with moisture collecting members.

This and further objects and advantages of the invention will be more clear from the following description of a preferred embodiment of the invention, reference being had to the accompanying drawing, in which,

FIGURE 1 is a horizontal axial section of the radially outermost portion of a radial flow turbine,

FIGURE 2 is a sectional view taken on line I-I--II of FIGURE 1. 1

Referring to the drawing the numerals 1 and 2 designate two oppositely rotating discs of a radial flow turbine. Said discs carry conventional blade rings to be operated by a radial flow of steam. Provided around the outermost blade ring 2 is a radial flow diffuser, the side walls 4 of which are annular and extending radially in planes at right angles to the axis AA of the turbine.

The annular space bounded laterally by means of the difiuser walls 4 are divided into a set of circumferentially spaced channels by means of partitions 6 extending in planes slightly inclined with respect to the axial planes that may touch the inner edges of the partitions (cfr. FIG. 2).

In each such channel there is provided a moisture collecting chamber 5 adjacent the partition 6 against which the moisture passing through the respective channel is thrown due to the combined action of the centrifugal force and the direction of rotation of the last blade ring of the radial flow turbine. Each chamber 5 is bounded on its one lateral side by the respective partition 6, at its outer end by a wall member 8 extending between the dilfuser walls 4 at the outer periphery thereof, and bounded at its inner end by a wall member 7 extending between the diffuser walls 4 at the inner periphery thereof. The side wall of each chamber 5 remote from the partition 6 is represented by a set of flutes 9 of sheet metal plates which extend axially between the diffuser Walls 4.

Formed in one difluser wall 4 near the inner end thereof are moisture outlet holes 12 leading to a discharge pipe 13 provided outside of said diffuser wall.

The steam leaving the blades 3' of the radially outermost blade ring 3 of the radial flow turbine, which is assumed to rotate in the direction indicated in the arrow R gets the direction of flow indicated by the vector 10 in FIG. 2, while the water particles adhering to the blades 3 are thrown out in the direction indicated by the vector '11. The sheet metal flutes 9' are such a profile as to catch the moisture thrown thereagainst and deflect it into the respective chamber 5 wherefrom it is drained through the openings 12 in the respective side Wall of the difiuser and the discharge tube 13, which may lead the water, say, to a preheater.

Surrounding the diffuser in radially spaced relation thereto is a deflecting member in the shape of an annular shield 14 presenting a laterally concave surface to the steam flow leaving the diffuser. As an alternative, the shield .14 may have the shape of an inverted V.

The concave surface of the shield '14 is lined by a moisture catching means 15 comprising, for instance, an assembly of wire netting, a perforated sheet metal plate or the like, which may catch the water particles and conduct them to discharge conduits 16, 16 leading, for instance, to a preheater. Said conduits 16 and 16 may act as supporting means for the shield 14.

Similar moisture deflecting members may be provided at opposite sides of the difiuser 4. Each such member comprises in the example shown a laterally carved annular shield 17 lined on its radially outwardly pointing surface by a moisture collecting material '18, as a wire netting or the like.

Since shield 14 has its lined concave surface pointing radially inwardly and the shields 17 have their lined concave surfaces pointing radially outwardly the steam leaving the diifuser will be first deflected inwardly by the action of shield 14 and then deflected outwardly by the action of shields 17.

We claim:

In an elastic fluid turbine in combination, a radial flow blade system, a stationary exhaust diffuser concentrically surrounding said blade system, said difiuser including two axially spaced annular walls provided at right angles to the axis of the turbine, and moisture collecting means in said exhaust diffuser comprising partitions extending crosswise between said walls in circumferentially spaced relation, means on the foremost surfaces of said partition walls as seen in the direction of rotation of the blade system for deflecting moisture against said partitions, and means for gathering and draining moisture thus collected by the said surfaces of the partitions.

References Cited in the file of this patent UNITED STATES PATENTS 1,695,751 Wiberg Dec. 18, 1928 FOREIGN PATENTS 528,254 Great Britain Oct. 25, 1940 619,722 Great Britain Mar. 14, 1949 

